Safety seat belt systems have been used in motor vehicles for many years. Traditionally, active seat belt systems have been used that require the occupant to actively participate in securing the belt and providing a safe driving environment. More recently, passive seat belt systems have also been used in the automotive industry which do not require the vehicle occupant to actively participate in securing the belt. Instead, a seat belt is automatically fastened around the occupant when he is in a seated position. This type of passive seat belt system has caused some degree of inconvenience to the drivers and passengers alike and consequently, has met considerable consumer resistance in using such passive systems. As a consequence, a combination of an active seat belt system and a passive restraint system (such as airbags) has been employed by many automobile manufacturers. This combination provides the convenience of an active seat belt system while still providing maximum protection when used with airbags.
In a conventional active seat belt system, an inertia sensor is used as an impact sensor and is mechanically linked to the seat belt retraction system. When the vehicle experiences a sudden deceleration, acceleration or sharp cornering, the inertia sensor senses such sudden motion and locks the seat belt retractor thereby retaining the seat belts securely on the driver or passenger. In more recent vehicle interior designs, seat belts are frequently integrated into the vehicle seat and mounted therein with a seat belt retractor.
This type of integrated vehicle seat/seat belt system is also desirable for vehicles equipped with convertible roofs. In these vehicles, the seat belt and the seat belt retraction system are mounted in the seat since there is no convenient pillar for mounting the turning loop. In some convertible vehicles, the seat belt retractor is mounted in the lower part of the vehicle body and the seat belt extends from the retractor, over the shoulder of the vehicle seat, through a harness and down to the lower part of the vehicle body. This design can cause discomfort to the seat belt wearer.
When a seat belt and a seat belt retraction system are mounted in the upper part of the vehicle seat, the inertia sensor which is normally mounted to the seat belt retractor can no longer be mounted together with the retractor. This is because the seat back of a vehicle seat is frequently tilted or reclined by a driver or a passenger for optimum comfort. In such applications, the change in orientation of the inertia sensor must be accounted for in order for the inertia sensor to operate properly. It is therefore desirable to mount the inertia sensor remotely from the seat belt retractor when the seat belt retractor is mounted in the vehicle seat. This type of remotely mounted inertia sensor for controlling a seat belt retraction system has been proposed by others.
One of such prior art method proposes mounting of an inertia sensor in the vehicle floor. In such applications, the inertia sensor functions as an electrical switch. When vehicle electrical current is turned on, current is fed to the system such that when the inertia sensor senses a sudden movement of the vehicle, it sends an electrical signal to either turn on or turn off a solenoid. The solenoid deactivates the seat belt retractor and locks the belt. One problem with such a system is that prior to the ignition switch being turned on, the seat belt retraction system is locked and as a consequence, the belt cannot be fastened by the driver or the front seat passenger of the vehicle. This type of ignition switch activated seat belt system is inconvenient. For instance, when the driver opens the vehicle door to fasten a child seat, the seat belt cannot be extended unless the ignition switch is already turned on. Furthermore, as soon as the ignition switch is turned off, the seat belt retractor is locked preventing any movement of the seat belt. This is inconvenient if the driver is still strapped in the seat belt. For instance, his motion will be restricted and he is prevented from reaching out and picking up personal item (e.g. an umbrella) from the floor area of the passenger seat.
It is therefore an object of the present invention to provide an active seat belt control system that can be mounted remotely from the vehicle seat to control the locking and unlocking of the seat belt retraction system.
It is another object of the present invention to provide an active seat belt control system that is remotely mounted from the vehicle seat that is not solely controlled by the vehicle ignition switch.
It is a further object of the present invention to provide an active seat belt control system that incorporates a logic circuit such that the seat belt retraction system is operable prior to and after the ignition switch is turned on or off.
It is yet another object of the present invention to provide an active seat belt control system that is remotely mounted from the vehicle seat and controlled by a logic and timer circuit equipped with a built-in inertia sensor and a seat belt in-use sensor.